Arm I: Patients receive isolated limb perfusion (ILP) with tumor necrosis factor (TNF) and melphalan. After the limb is warmed, TNF is injected into the arterial line of the extracorporeal ILP circuit over 2-3 minutes beginning at time 0, and perfusion proceeds for another 25 minutes. Melphalan is injected into the same line over 3-5 minutes and perfusion with both drugs continues for another 60 minutes.